You use Import Records to import all the records from all the tables in the old version into the new. You also update the next serial value settings of any auto-entered serial numbers to prevent records added after the import from generating values that duplicate a record from the imported data.

This can be scripted so that you can send out the new file, the users open it and click a button--producing a dialog box where they select the old copy of the database and the script takes it from there.

You can also design your files using the Convert to Seperation Model model and thus greatly reduce the circumstances where such an import of the data is needed.